Welcome to your interview.
The question is on your right: Build a Minimal Gist Viewer. Take a moment with it first.
Talk your thinking through with me if you like - when you're confident, submit your answer and I'll grade it like a real screen (7/10 or better passes). Discussion and graded submissions share your five interviewer interactions, so spend them well.
Make a GitHub Gist viewer with very few external libraries allowed (e.g., no styling libraries, no routing libraries). It needs some basic routing so you can search for gists by username, paginate gists, search for a gist by ID, and get files for the gist.